Saturday, February 15, 2014

Additional Info for the Line Following Robot Design

Attached are jpeg files of the additional info regarding the hardware of the line following robot.

The power source configuration shown in the picture below is the one shown in class. Its advantage over the other configuration (to be shown later) is that it only uses one source (4xAAA Batteries). The down side with this configuration is that the mCU and as well as the logic circuit inside the L293 IC are easily affected by the transients caused by the 2 DC Motors when they turn on. If the your mobile robot seems to hang up, then you might want to try the other configuration.

The alternative power source configuration is shown in the picture below. This configuration uses two sources, one source solely for the the DC motor (connected to the VCC2 pin of the L293D ic) and the other to source both the mCU (via the LM317 ic) and the logic circuit inside the L293 ic (connected to the the VCC1 pin of the L293). The advantage of this kind of configuration is that the effects of the DC motor transients are minimized, thus your line following robot is more stable. The downside is that you will be needing 8 AAA batteries in 2 "4xAAA" group.

In both configurations, some pins of the Z8F0822A mCU IC and L293 Motor Driver IC are omitted for simplification purposes. They are still needed in the real circuit, the ones shown in the picture is simply to emphasize on the power source connection.

There are lot of comparator IC sold in the market. The ones I have used so far for line following robot purposes are shown in the picture below. The circuit for a light sensitive sensor is also shown.

 A bright LED should be soldered close to the LDR. This will give off the light needed by the LDR to detect the black line on the track. A picture of an actual LDR and LED circuit is shown below.

You are encourage to download the pics as a guide.

Let us win this!!!!

Go Geeks!!!

 Hope this post helps :)

See you all at the 2014 Robotics Competition!!!

Sunday, July 21, 2013

The "MoBotGeek Initiative"

Having been brainstorming for a Thesis Topic for my Masters Degree, I have come up with an initiative. The plan is create a Z8F4821 mCU Based I/O board to be used as an interface board for known sensors in the market. "Shared Library" for C++ Programming will be created for each sensor so as to unburden the user from the details of configuring the mCU as an interface board between the sensor of choice and a desktop computer.This board is envisioned to used in research studies and hobbyist projects.

These are the initial features of the board:
  • Analog Input
  • SPI Input
  • UART Input
  • I2C Input
  • D.I/O
  • and PWM
Features will be changed as per advice of my Mentor and "Special Problems Class " Professor.

You can send your advises and/or suggestions regarding the board through posting. 

Will be posting more details and updates regarding this.

Hope to see you in my next posts.

Friday, April 19, 2013

Alitaptap - A Strobe Light Controller for Motorcycle LED Strip Aesthetics Lighting

I just recently bought a secondhand Honda Ex3 Malaysia Motorcycle.

After having its engine and other mechanical parts restored to its optimum condition, the next thing I had in mind is to add aesthetic lighting. I went to a local electronics store and found these 12V DC Operated LED Strip. These are perfect for what I had in mind.

These LED strip are low profile and sealed. Unfortunately, they operate at 12V DC while my motorcycle electrical system can only supply a maximum of 6V DC.

Luckily, I remembered the voltage doubler circuit introduced to us in our Electronics class during my college years. The voltage doubler circuit introduced to us at that time needs an AC input. Though its not the right circuit for my problem but it gave me a reason to look for a voltage doubler circuit that works with DC input. The search led me to this very cool site full of interesting useful circuits, the Out from which I got this circuit This site did not only post the circuit schematics but also a detailed description of how the circuit works.

Since some of the components shown in the circuit schematics is not locally available, I had to replace them with similar components that are available here in my place.  The schematics of the modified circuit is shown in figure below.

(Replace the 1N4001 with 1N5818 if the later is available. The 1N5818 has lesser threshold voltage thus the final output has a lesser drop in voltage. )

Bought and soldered all components into a perforated board. The resulting circuit is shown in the following figures.

The last picture shown above shows the copper portion of the perforated board and the solder bridges made to connect the pins of the circuit components.

I tested this circuit using a 5V DC input. The output voltage measured, using my analog multimeter, is 8V. Theoretically, it should have been 10V but due to the diode and transistor P-N junction threshold voltages, the output voltage is minimized to 8V.

Tested this circuit again using the battery of my motorcycle and with the LED Strips connected to the output port. As can be observed, the LED Strip lights up brightly.

The power supply part is done. The next part is the strobe controller which I will be calling as Alitaptap. Alitaptap is the Filipino term for firefly. I have decided to make one out of the NE555 Timer in Astable Multivibrator (with diode) Configuration. The circuit schematics is shown below.

This circuit is the same with the clock generator part of the voltage doubler circuit shown previously. Its only difference is that of its output frequency which is lower than that of the previous circuit. I have included a potentiometer or variable resistor into it to allow for adjustments of the output Duty Cycle or simply put the ration between the on time and the total period.

In summary the Alitaptap strobe light controller is a Fixed-Frequency-Variable-Duty-Cycle-NE555 Based Astable Multivibrator circuit.

Assembled it on a perforated board. The resulting circuit is shown in the following pictures.

The complete device, which is composed of the voltage doubler from, the Alitaptap strobe light controller and the LED strip, is shown in the following pictures.

Pictures of how I installed the whole device into my motor cycle will be posted later.

That's it for now.

Thank you for reading once again.


Friday, April 20, 2012

"Kutitap" - An Anomalous Light Monitoring System

Due to recent events relating to anomalous light incidents witnessed by a friend, I have decided to fabricate a device that will help me monitor the light phenomena with in my home area.

I will be calling it "Kutitap". It is a device that will help me monitor the light phenomena within my home area by logging the light intensities from 7:00 PM in the evening till 4:00 AM in the morning, while I am asleep.

The concept design is shown in the figure below.

By logging  the light intensities within my home area at periodic time intervals from 7:00PM to 4:00AM, the following day, I would be able detect anomalous light activities by examining the graphs (light intensity as a function of time) of the logged data.

My hypothesis is that anomalous light activities would be shown as "high spikes/peaks" in the graphed data. This is because at normal night (no anomalous light phenomenon), light intensity levels vary so little. And since anomalous light phenomena are characterized by high intensity lights, either at short or long duration, this will be shown as high variations in the light intensities.

This "high spikes/peaks" would then be observed through examining succeeding graphs. Its intensity and time of occurrence will be recorded. If such spikes persists within the light intensity graphs of the next 5 days, further investigation will follow.

Further investigation will comprise of a "sky-pointing video camera (and other optical monitoring/sensing systems at hand)" along with actual ocular investigation within the time the spike in the graph was observed to occur.

With this, I hope that I would be able to shed "LIGHT" to this anomalous "LIGHT" occurrences.


Friday, March 2, 2012

4-1 Run Pace Calculator

This project has nothing to do with robots, microcontrollers or electronics, but I have decided to include this here as I consider this as a fun endeavour. I found this fun not only because it is an intellectual exercise but because I used the actual calculator in computing for my first 42K Run/Walk Pace during the 2012 Cebu City International Marathon.

The objective of this projects is to create an online calculator that will compute for the "Run/Walk Pace" when using the "4-1 Style of Marathon Running". 

It is consist of 2 parts, the derivation of the working equation and the implementation of the actual "Running Pace Calculator" for the "4-1 Style of Marathon Running". 

The paper detailing the Equation Derivation can be found here. And the actual online calculator is found here.

That's it for this project.

Keep running!!!


Thursday, March 1, 2012



I am Johnson, a.k.a the MoBoTGeek.

I have decided to created a Blog to document the stuff I have have been doing relating to mobile robot, microcontroller and other electronics projects.

As planned (hoping to follow it), blog entries will all be introductions to a project that I have completed. Details of it will all be written using LaTeX2e and posted in PDF format.

If there are stuff you think I am capable of building/making or if there are stuff you think I can help you with, please feel free to e-mail me and will be posting replies in the form of a Blog or if needed, a PM.

Well, that's it for my first post. Allow me to end it, with my favorite line from my favorite movie, Star Wars, "May the Force be with you!!!".

Till my next post.